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1. Field of the Invention
This invention relates to freeze proof hydrants with provisions for preventing backflow from an attached hose into the water supply system.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
It is crucially important that a potable water system not be contaminated. A common source of such contamination is water hoses connected to wall hydrants which provide potable water. The water supply within a building normally consists solely of potable water. This water supply also normally is used to provide water for use outside the building through a wall hydrant. Such water is used for watering a lawn, garden, washing a car, etc using a hose attached to the wall hydrant.
A threat to the integrity of the potable water supply inside the building is created when a hose is connected to a wall hydrant, the hose is used, and the water supply is turned off at the wall hydrant. Non-potable water from the attached hose presents a threat to the potable supply on the other side of the hydrant through two separate mechanisms. Pressure from the water in the hose may flow back through the hydrant into the water supply. In addition, a lowering of pressure inside the building may create a back-siphonage condition which causes non-potable water from the hose to enter the potable water system within the building. Finally, freezing of the hydrant may damage the valve in the hydrant and allow backflow from the hose into the potable water system inside the building.
U.S. Pat. No. 4,109,671 discloses a nonfreezing yard hydrant which has provisions for draining the water from the upper portion of the hydrant to below the frost line.
U.S. Pat. No. 4,221,233 and U.S. Pat. No. 4,286,616 disclose a non-freeze wall hydrant which is self-draining and has a comparatively simple vacuum breaker incorporated in the fluid path.
U.S. Pat. No. 4,712,575 discloses a self-draining hose connection vacuum breaker and backflow preventer. The connection is self-draining when no hose is connected and the backflow preventer moves into place when a hose is connected.
U.S. Pat. No. 4,821,762 discloses a freezeless wall faucet which moves from fully open to fully closed position in rotation through 360 degrees. A vacuum breaker is open to the atmosphere except when the faucet is full of water and a spring loaded backflow preventer keeps water from returning from the faucet to the supply line.
U.S. Pat. No. 4,844,116 discloses a quarter turn water hydrant with a valve structure incorporating ceramic components. The disclosures of U.S. Pat. No. 4,844,116 are incorporated herein by reference.
U.S. Pat. No. 4,893,654 discloses a double check valve backflow preventer assembly which uses two separate check valves mounted in series within a single housing to allow flow of fluid in one direction only.
U.S. Pat. No. 4,909,270 discloses a anti-siphon frost free faucet which includes a vacuum breaker, an anti-backflow valve at the hose connection, and a drain valve at the lowest portion of the faucet, the drain valve having a spring-loaded plunger which is biased the open position, and is moved into the closed position when water is flowing-through the faucet.
U.S. Pat. No. 5,012,833 discloses a freeze-proof hydrant which includes a replaceable valve cartridge as well as a backflow preventer at the hose connection.
U.S. Pat. No. 5,029,603 discloses a frost-proof water hydrant which includes two anti-backflow valves and a drain hole and an air valve. Air is admitted to the faucet when the faucet is in the closed position.
U.S. Pat. No. 5,158,105 discloses an anti-siphon freezeless hydrant with a housing integral with a hose connection. Complete closure of the water valve opens holes which admit air into the faucet and encourages drainage of water from the faucet.
U.S. Pat. No. 5,217,039 and U.S. Pat. No. 5,288,470 disclose an automatic draining back flow preventer with two diaphragms and air ports located between the diaphragms. Flow from the faucet causes the first diaphragm to block the air ports while the flow exits through the second diaphragm. Cessation of flow allows the first diaphragm to flex exposing the air ports for drainage of the hydrant, and backflow is blocked by the second diaphragm.
U.S. Pat. No. 5,392,805 discloses a frost-resistant hydrant with a 90 degree ceramic valve having a combination back flow preventer and vacuum breaker in the flow stem.
U.S. Pat. No. 5,590,679 discloses a water hydrant with backflow and siphonage preventer and a vacuum breaker. The backflow preventer is made of elastomeric material which is deflected toward the axis of the cylindrical body during normal flow and is deflected outwardly from the axis to seal the body during backflow.
U.S. Pat. No. 5,740,831 discloses a hydrant seal which is resilient and surrounds the stem and which prevents backflow.
U.S. Pat. No. 5,752,542 discloses a faucet with a resilient annular check valve about the stem which blocks backflow.
U.S. Pat. No. 6,142,172 discloses a freeze protected hydrant with a relief valve which releases water trapped in the hydrant. An annular resilient check valve surrounds the stem and acts as a backflow preventer.
None of the prior art hydrants have the advantages of the hydrants of the present invention, that of being automatically freeze protected, and having dual independent biased check valves with an atmospheric vent biased in an open position located between the two check valves.
This invention is a wall hydrant which comprises a body having a front and a back, a tubular casing attached at a first end to the back of the body, and a valve assembly attached to the tubular casing at a second end of the tubular casing via a valve housing. The valve housing is connected to a source of water.
A wall plate is attached to the front of the body. A hydrant control knob extends through the wall plate, the hydrant control knob having an open and a closed position. The hydrant control knob is attached to a control tube at a first end, and the control tube is attached at a second end to the valve assembly. The valve assembly admits water into the hydrant when the hydrant control knob is in the open position and the valve assembly does not admit water into the hydrant when the hydrant control knob is in the closed position.
A backflow preventer having an inlet and an outlet is attached to the front of the body at the inlet, the backflow preventer having a hose connector at the outlet, the outlet extending through the wall plate adjacent to the control knob.
The backflow preventer further comprises an inlet check valve and an outlet check valve, each valve biased in a closed position, wherein both the inlet check valve and the outlet check valve prevent flow from the outlet into the hydrant body. An atmospheric vent is located between the inlet check valve and the outlet check valve, the atmospheric vent biased in an open position when water is not flowing through the hydrant and the atmospheric vent dosed when water is flowing through the hydrant.
A wall hydrant comprising: a body having a front and a back, a tubular casing attached at a first end to the back of the body, a valve assembly attached to the tubular casing at a second end of the tubular casing via a valve housing, the valve housing connected to a source of water, a wall plate attached to the front of the body, a hydrant control knob extending through the wall plate, the hydrant control knob having an open and a closed position, the hydrant control knob attached to a control tube at a first end, the control tube attached at a second end to the valve assembly, the valve assembly admitting water into the hydrant when the hydrant control knob is in the open position, the valve assembly not admitting water into the hydrant when the hydrant control knob is in the closed position, and a backflow preventer having an inlet and an outlet, the backflow preventer attached to the front of the body at the inlet, the backflow preventer having a hose connector at the outlet, the outlet extending through the wall plate adjacent to the control knob, the backflow preventer further comprising: an inlet check valve and an outlet check valve, each valve biased in a closed position, wherein both the inlet check valve and the outlet check valve prevent flow from the outlet into the hydrant body, and an atmospheric vent located between the inlet check valve and the outlet check valve, the atmospheric vent biased in an open position when water is not flowing through the hydrant, the atmospheric vent closed by the inlet check valve when water is flowing through the hydrant.
Freeze resistance is obtained by allowing water to drain from the hydrant when the control knob is in the off position. The hydrant has a drain deflector having a fillet, a fixed operator piece having two holes, the fixed operator piece mounted adjacent to the drain deflector, a movable operator piece connected to the control knob, the movable operator piece having two holes, the movable operator piece mounted adjacent to the fixed operator piece, the movable operator piece movable between an open position and a closed position, wherein the holes in the fixed operator piece are aligned with the holes in the movable operator piece when the movable operator piece is in the closed position, thereby allowing water to drain from the hydrant body through the holes in the movable operator piece, the holes in the fixed operator piece, and the fillet in the drain deflector.
The American Society of Sanitary Engineering (ASSE) has published performance requirements for vacuum breaker freeze resistant, automatic draining wall hydrants. American Society of Sanitary Engineering, Standard #1019, Performance Requirements for Vacuum Breaker Wall Hydrants, Freeze Resistant, Automatic Draining Type, Westlake, Ohio, 1997. Such hydrants are freeze resistant through an automatic draining provision which drains the water from the hydrant when water is not flowing through the hydrant. Hydrants which comply with this Standard also are protected against contamination of potable water through backflow of water from a connected hose. The means of prevention of such backflow are termed xe2x80x9cvacuum breakersxe2x80x9d. In particular, such hydrants must be protected against backflow from a hose filled with water with backpressure equal to 10 feet of head pressure. Three distinctive Types of hydrants are classified; Type A are hydrants which automatically drain the water when the water supply is shut off and the hose removed to prevent damage from freezing. Type B hydrants automatically drain the water with a hose removed or attached, and nozzle closed, and the hydrant valve closed. Type C are the same as Type A, but backflow prevention is achieved by alternate principle of holding pressure versus relieving pressure
The ASSE has published performance requirements for hose connection backflow preventers. American Society of Sanitary Engineering, Standard #1052, Performance Requirements for Hose Connection Backflow Preventers, Westlake, Ohio, 1994. Such backflow preventers protect against both back siphonage and backpressure backflow of water from a hose. Such devices contain two check valves on the discharge side of a hose threaded outlet on a potable water system and protect against a backpressure generated by an elevated hose equal to 10 feet in height. The checks are independent, force loaded or biased to a closed position. In addition, there must be an atmospheric vent located between the two check valves, force loaded or biased to an open position, and means for attaching a hose.
The hydrants of the present application meet the requirements of both ASSE Standard #1019 Type A and Type B, and ASSE Standard #1052. These hydrants provide superior automatic protection against freezing and against backflow, thereby avoiding the contamination of potable water despite freezing conditions and despite conditions of backpressure or of back siphonage.
An objective is to provide a hydrant with automatic resistance to freezing and freeze damage.
Another objective is to provide a hydrant with automatic resistance to contamination of potable water due to backflow of water from an attached hose.
Another objective is to provide a hydrant with protection against contamination of potable water due to backflow of water due to backpressure.
Another objective is to provide a hydrant with protection against contamination of potable water due to backflow of water due to back-siphonage.
Another objective is to provide a hydrant with a dual check valve backflow preventer.
Another objective is to provide a hydrant which automatically drains the water with a hose attached and nozzle closed, and the hydrant valve closed.
Another objective is to provide a hydrant with dual independent check valves in a backflow preventer.
Another objective is to provide a hydrant with spring biased dual independent check valves in a backflow preventer.
Another objective is to provide a hydrant with an atmospheric vent biased to an open position located between dual check valves.
A final objective of this invention is to provide a hydrant which is easily manufactured of inexpensive materials without adverse effects on the environment.